> Govt buildings have lens detectors.

Care to explain? If I point a camera at my local Fed building while walking on the nearby sidewalk, are you telling me that's detected somewhere?

I have heard stories of feds coming out to stop people taking pictures of federal buildings. Always assumed it was security policy, but would be funny if it was just,

"Damnit that guy is making this alarm go off non-stop, Dave, go get him to move along"

Not a technical explanation but a story about a similar thing:

https://www.wired.com/2009/09/russian-billionaire-installs-a...

I remember this article as the first time I learned that photo-taking can actually be detected. Given that it was written in 2009, I imagine that the general camera-detecting technology has been mostly figured out by now.

So when it detects a lens, it shoots light to destroy the photo.

If the detection is not ideal, it could detect eyeglasses and shoot light into people's eyes

I'm surprised it works outdoors, I would think the red light would be impossible to pick out of a high resolution image even with a fine filter.

As far as I understand, these laser scanners work outdoors in daylight:

https://www.popsci.com/technology/article/2013-05/laser-scan...

> Lasers sweep the surroundings and when they detect a CCD, they fire a bolt of light right at the camera to obliterate any photograph

Color me skeptical. Does it detect the lens in the eye too? And then? Does it obliterate my retina when I look at his yacht?

If you've got a CCD in your eye then ya, I'd be concerned about that.

I'm not going to pretend to understand the physics at play, but is there perhaps lens coatings or materials that reduce the chance of detection?

yes thats what the red "ruby" lens coating is about, it buffers reflection from the lens surface.

https://en.m.wikipedia.org/wiki/Optical_coating